Well it certainly sounds interesting.
I have learned not to trust photographs when it comes to interpreting colours. Sometimes it's the sun, sometimes it's the film, sometimes it's.. well... both you and Graham knows about this, Steven.
I have not seen the profile but I'd like to know if it's with original black or white letters in order to pinpoint the date a bit more. Also, being an RD-serialled bird, has it got the extended fin and thimble radar?
My guess is it's a one-off. Perhaps they tested out a whitewash? Or a sealer? Perhaps they were sending the aircraft to Amarc?
As for Grahams 2G I have also seen this photograph and suspects it to be either overpainted anti-uboat paint or perhaps just dirty white and low contrast exposure. I have seen grey look like white and vice versa. Here's my interpretation of the anti-uboat scheme used by 236 Sqn down in Cornwall. Should be dated some time in the autumn of 43.
